I just upgraded my 20 gallon tank to a 29, and moved all the fish from the 20 to the 29. The water parameters were virtually identical in the two tanks, and all the fish are doing well in their new digs except the two otos, who haven't done anything except lie around on the leaves of the plants. Prior to moving them, they were doing great - were very active and all over the tank, and I've had them for months. Could they just be adjusting to the new tank, or are they doomed? Anything I can do for them?

if you have any other tanks with algae scrape as much off as you can and put it in the tank, this could possibly cause a algae bloom but very unlikey (thanks to the ottos). also, cut up a peice of cucumber and drop it in, they will eat that.

also, see if later when the takn is more mature you are able ot pick up a few more ottos, they are schoolnig fish and should be kept in groups. keep in mind though unless the tank is right beside or in front of a window there will not be enough algae to go around and adding cucumber and other vegies will be needed. good luck!_________________"I am a wildlife warrior, and I will fight, fight to the death for wildlife." - Steve Irwin

Thanks - they actually went into an established tank, the old occupants moved up to a 55 gal. There's no problem with algae supply plus I give them algae wafers, I'll put in some cucumber tonight. I'm just wondering if anyone's had otos act so lethargic and then recover. The water parameters are fine and are the same as the tank they moved out of, so I'm not sure why they're having trouble. They still have round bellies but I haven't seen them do anything but lie around.

If it's been less than five or six days since you moved the Otos, I wouldn't do anything: no special foods, no water changes, just plain nothing. Otos often take a bit longer than many other commonly kept fish to adjust to new surroundings.

Give them a little time and as little distrubance as possible. They will mostly likely be just fine especially since their 'new' tank is really a well-established one with plenty of algae already there.

Maybe Deborah_claro will jump in on this post - she is the guru on all things Oto.

Otocinclus do not like any changes in a tank, and that's that. Moving them to another tank constituted a change. If the water parameters are truly the same from one tank (the 20G) to the other (the 29G) as you say, then there should not be a real problem. You could double-check the water conditions, if you want to, but if all is okay then do not make any other changes. Make sure the water current is brisk. Do not overfeed in an effort to "make up for" the move. They don't need extra food. Do not do unnecessary water changes, either; they won't help and will probably hurt. Just stick to your regular water changing schedule. If you need to do a water change before then, break it up into two or three small ones a couple of days apart, each. The fewer new things you do now, the better.

Give them a chance to find new hiding and resting places. Do you have a piece of slate leaning up against the back wall? They'd like one. Typically, otos are not all that active and don't scamper around a tank. Too much activity can signal that something is wrong, and usually precedes a downward spiral. Lying around on the leaves of plants is what they do - it doesn't sound serious to me, but you know your fish better than I do. I wish I could see them - I'd know in a minute if they were okay.
Otocinclus really do not need to be kept in groups, and your two are fine as is. If they were fine for the preceding months that you've had them, they should be fine again. Just give them a while to settle in.
I hope this helped.
Please keep us posted.
Deborah_________________

In addition maybe you can dim the lighting for a day or two while they acclimate as well. I also heard from another Oto expert to add oxygen into the water by dropping the level a little, etc.

When my Otos about 2 weeks ago went very lathargic, I ruled out any water quality problems, added more shelter/plants, and just used ambient lighting in the room, and didn't use the aquarium light. After a few days, they were better than they were before._________________12g Eclipse

Thanks for all the replies. As of today they are still alive and I'm optimistic that they're going to be OK, and I'm finding them in different places so they're moving at least a little around the tank. In the old tank they were usually actively eating at all times and sometimes swimming energetically with the cories. I didn't think about the lights, which is interesting, because the lights are brighter in this new tank than in the old - I just turned them off and we'll see if that has any effect. The tank has lots of live plants and hiding places so hopefully they'll be back to their old selves soon!

Well, as of this morning I think they're worse... they're both alive but one is hanging out on the heater at the very top of the tank, the other near the top on the filter intake tube. I've had other otos who did this and died not too long later. If there's anything I can possibly do to save them, I'd love to hear. They've been in this new tank for a week and I was going to do a water change tomorrow, but it it could possibly help I can do one today. But unfortunately, I'm losing hope

This is very odd, even for Otocinclus. What temperature is the water? Is it appreciably different from the tank water that they used to be in (the 20G)? Specifically, is it higher? If it is, that may be the problem.

Did you disturb the substrate when you moved the fish to the 29G?
Could something have been released into the water? If you think so, then do the water change but, if you can, break it into two parts. That is, do half now, wait an hour or so to see how they do, and then do the other half.

My otos cling to the filter intake from time to time - they like the feel of the tug of the water. It reminds them of the brisk current in their natural habitat. They do tend to set themselves in the area of the most current. It's best if the area where the water returns to the tank is a safe and sheltered area for the otos. That's where they will like to hang out, but they need to feel safe there.
You might need to increase the water current a little. Is there a way you could place the filter return a little lower in the tank?
Or could you create a waterfall? NeonJulie suggested dropping the water line a little. That would help in two ways - you'd get a waterfall, and it would drive more oxygen into the water. Some power filters have an option to increase the flow of the water return to the tank.

If both of your otos were hanging around on the filter intake, I'd feel more confident that it was a water current issue only, and possibly a heat issue, too.

But the one hanging around on the heater worries me. Is the heater on when he does this? Do you think the fish just wants to be near the top? Near the surface to have access to more oxygen? Can you slip a small airstone into the tank? Do you have one? You can get a package of airstones, several feet of silicone tubing, and a small air pump for $13-$15 at PetSmart. Wal-Mart should have similar items. It's not too expensive, and all, but the airstones, can be reused.
I'm really sorry this has happened. Upgrading them to a bigger tank should not end in disaster.
I would try the water current option or the airstone option.
Let us know how things are going.